This invention relates to a multi-element metallic composite alloy, a process for producing such a composite, an electrical contact and spring member assembly fabricated from such a composite, and a method for producing such an assembly. More particularly, this invention relates to a multi-element metallic composite alloy comprising at least one base metal alloy constituent which is metallurgically bonded to at least one noble metal alloy constituent, and to a process for producing such a multi-element metallic composite alloy. The composite and process of the instant invention are particularly useful in fabricating electrical contact materials which have enhanced electrical and mechanical properties. This invention also relates to an electrical contact and spring member assembly in which the contact portion, which comprises at least one noble metal alloy, is metallurgically bonded to the spring member portion, which comprises at least one base metal alloy, and to a method for producing such an assembly.
The use of base metal alloys as electrical connectors is well known to those skilled in the art due to their enhanced formability during processing, enhanced spring properties after aging, stability during age hardening, elevated temperature stability in service. It is also well known to those skilled in the art that noble metal alloy materials have excellent electrical conducting properties and are useful in a variety of electrical and electronic applications; for example, as a sliding contact in precision potentiometers, such as might be found in automobile engine control systems. However, the fabrication of electronic components from solid noble metal alloy materials is extremely expensive. In addition, such alloys tend to be brittle, lacking the spring properties and elevated temperature stability of base metal alloys. It would therefore be highly advantageous if the properties of noble metal and base metal alloys could be combined in a single composition from which electronic components and other materials requiring these properties could be fabricated.
It is one object of this invention to realize the potential of multi-element alloy composites by providing a process by which noble and base metal alloys may be metallurgically bonded together. It is one feature of this invention that the composite alloy combines the high spring properties of the base metal alloy with the superior electrical contact properties of the noble metal alloy.
The composite alloy of this invention is advantageous in that it has enhanced electrical and spring properties, greater stability at elevated operating temperatures, experiences minimal distortion while being age hardened, exhibits improved elevated temperature relaxation properties, and exhibits no formation of intermetallics and complex or undesirable alloys in the bond area between the dissimilar alloys, thereby enhancing its electrical and mechanical properties. The process of the instant invention is advantageous it that it produces a composite alloy composition having the above-described properties. The composite alloy and process of this invention may be used in any electrical contact application such as in potentiometers, switches, relays, contacts and the like. Such devices may be employed in a variety of commercial, industrial, and research settings in a variety of products.
Another advantage of the composite and process of this invention is that the age hardening characteristics of the noble and base metal alloy constituents are both enhanced and made compatible to one another as compared with each constituent's unbonded natural state. More particularly, the composite and process of this invention are advantageous in that the hardening characteristics of the composite are improved and equalized when compared to bimetallic alloy compositions comprising alloys of beryllium-copper and beryllium-nickel.
The electrical contact and spring member assembly of this invention is advantageous in that is combines the excellent electrical properties of the noble metal alloy and the excellent strength and stability properties of the base metal alloy. The assembly is also advantageous in terms of cost, as less of the more expensive noble metal alloy material is required since the spring member is fabricated from the base metal portion of the composite alloy. The method of this invention is advantageous in that it produces the assembly, which has many commercial uses.
This invention is also advantageous in that it specifically excludes the use of beryllium-copper alloys as the base metal constituent, thereby avoiding the extra processing and special handling ordinarily required for toxic beryllium-containing materials.